The rainbow hills: why the earth near Gareji is striped

By Prof. Giorgi Pkhakadze, MD, MPH, PhD · 15/09/2026

Updated 23 October 2026

Somewhere past Sagarejo, on the road south-east from Tbilisi, the land changes. The vineyards stop, the villages thin out, and the hills on either side begin to show colour: a red band, then a white one, then a rusty orange, then a grey-green, repeating up the slope like the layers of a cake sliced open. In spring, with the grass short and green between them, the effect is startling. In summer, with the grass gone gold, it is stranger still. Georgians call them the rainbow hills; geologists call them the Gareji badlands; both are right.

The sea

Fifteen million years ago the plain south-east of Tbilisi was the floor of a shallow sea — the Sarmatian, an arm of the great inland ocean that stretched from Vienna to the Aral. Rivers from the young Caucasus poured sediment into it: red and brown mud rich in iron from the volcanic mountains, pale limey ooze from the shells of sea creatures, grey-green clay, sand. Each layer settled on the last as the sea rose, fell and shifted. When the sea finally drained, the layers were a mile thick. Then the land was lifted and tilted by the mountains still rising to the north, and the rivers and rain of a few million years cut through the tilted layers and exposed them on the slopes, band after band.

The colour is chemistry: iron oxidised red, iron reduced green, lime white, manganese purple-black. The absence of vegetation on the steeper slopes — the clay sheds water and grows almost nothing — keeps the colours bare. Rain deepens them; the hour after a spring shower is the time to be there.

The steppe

The rainbow hills sit within the Iori plateau, a semi-desert of grass, wormwood and juniper that is unlike anything else in Georgia — the country’s little piece of Central Asia. It is home to gazelles reintroduced in the last decade, to tortoises, to eagles, vultures and, in the cliffs, to the last colonies of the imperial eagle in the Caucasus. Shepherds bring flocks down from Tusheti to winter here. The Vashlovani national park, further south-east, protects the finest of it, with mud volcanoes, pistachio woods and a border with Azerbaijan.

The road

The colours are best seen from the road itself in the last twenty kilometres before David Gareji, where it runs along the crest of the badlands with the layered hills on both sides. Stop at the viewpoints; walk a hundred metres off the road onto a ridge; the silence and the scale come up around you. The monastery, when it appears, is set into a striped cliff of the same rock — the monks chose their colours well.

See it with GTour

The rainbow hills are the approach to the David Gareji day trip; we stop where the colours are best, and spring departures are timed for the green.

This story in Georgian — ქართულად: shenidasveneba.ge

Quick answers

What are the rainbow hills and where are they located? The rainbow hills are striped badland hills found along the road south-east from Tbilisi, past Sagarejo, leading toward David Gareji. Geologists call this area the Gareji badlands, and the colourful bands appear in the final twenty kilometres before reaching the Gareji monastery.

Why are the hills striped with different colours? The stripes formed about fifteen million years ago when the area was the floor of the Sarmatian Sea, an arm of a great inland ocean, and rivers from the young Caucasus deposited layers of iron-rich red mud, pale limey ooze, grey-green clay and sand. After the sea drained, the land was uplifted and tilted by the rising Caucasus Mountains, and erosion cut through the layers to expose the bands on the slopes.

What causes the specific colours seen in the hills? The colours come from chemistry: oxidised iron creates red, reduced iron creates green, lime produces white, and manganese gives purple-black tones. Because the clay sheds water and little vegetation grows on the steep slopes, the colours remain bare and visible, becoming deeper and more vivid after rain.

What region do the rainbow hills belong to, and what makes it unique? The rainbow hills lie within the Iori plateau, a semi-desert landscape of grass, wormwood and juniper that is unlike anywhere else in Georgia, often described as the country's own piece of Central Asia. It supports reintroduced gazelles, tortoises, eagles, vultures, and the last colonies of the imperial eagle in the Caucasus, with Tusheti shepherds bringing flocks here to winter.

Is there a protected park near the rainbow hills? Yes, the Vashlovani national park lies further south-east of the rainbow hills and protects the finest part of the Iori plateau landscape. It features mud volcanoes, pistachio woods, and borders Azerbaijan.

What is the connection between the rainbow hills and David Gareji monastery? The rainbow hills form the scenic approach to David Gareji, with the monastery itself set into a striped cliff made of the same colourful rock layers. The article notes that the monks who built it chose their colours well.

When is the best time to visit the rainbow hills for the most striking views? Spring is ideal, when the grass is short and green between the colourful bands, creating a startling effect, and the hour after a spring shower deepens the colours even further. In summer, when the grass turns gold, the hills look stranger still, offering a different but equally compelling view.

Photo: Jacob van Ruisdael / Wikimedia Commons, Public domain